Cooperative transceiving between wireless interface devices of a host device with shared modules

ABSTRACT

An circuit includes a first wireless interface circuit that transceives packetized data between a host module and a first external device in accordance with a first wireless communication protocol. A second wireless interface circuit transceives packetized data between the host module and a second external device in accordance with a second wireless communication protocol. The second wireless interface circuit includes at least one module that is shared with first wireless interface circuit, the module having a first state where the module is operational and a second state corresponding to a low-power state. The first wireless interface circuit and the second wireless interface circuit operate in accordance with a wireless interface schedule that includes a first time interval where the first wireless interface device and the second wireless interface device contemporaneously use the at least one module in the first state and a second time interval where the at least one module is in the second state.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to wireless communication systems andmore particularly to cooperative transceiving by wireless interfacedevices of the same host device.

2. Description of Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11,Bluetooth, advanced mobile phone services (AMPS), digital AMPS, globalsystem for mobile communications (GSM), code division multiple access(CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, etcetera communicates directlyor indirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel or channels (e.g., one of the pluralityof radio frequency (RF) carriers of the wireless communication system)and communicate over that channel(s). For indirect wirelesscommunications, each wireless communication device communicates directlywith an associated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the transmitter includes a datamodulation stage, one or more intermediate frequency stages, and a poweramplifier. The data modulation stage converts raw data into basebandsignals in accordance with a particular wireless communication standard.The one or more intermediate frequency stages mix the baseband signalswith one or more local oscillations to produce RF signals. The poweramplifier amplifies the RF signals prior to transmission via an antenna.

As is also known, the receiver is coupled to the antenna and includes alow noise amplifier, one or more intermediate frequency stages, afiltering stage, and a data recovery stage. The low noise amplifierreceives inbound RF signals via the antenna and amplifies then. The oneor more intermediate frequency stages mix the amplified RF signals withone or more local oscillations to convert the amplified RF signal intobaseband signals or intermediate frequency (IF) signals. The filteringstage filters the baseband signals or the IF signals to attenuateunwanted out of band signals to produce filtered signals. The datarecovery stage recovers raw data from the filtered signals in accordancewith the particular wireless communication standard.

The 2.4 GHz industrial, scientific and medical (ISM) band isexperiencing unprecedented growth due mostly to strong showing of twowireless technologies: wireless local area networking (WLAN) andwireless personal area networking (WPAN). WLAN operates in the 100+meters range and is usually used to augment traditional wired networkingby providing wireless connectivity in the home, office or public areas.WLAN devices operate in accordance with IEEE 802.11 standards (802.11b,802.11 g and 802.11n) and offer data rates in excess of 100 Mbps. Inrecent years as the voice over IP (VoIP) finds wider adoption forcarrying telephone traffic, various new concepts such as UnlicensedMobile Access (UMA) have been using WLAN as a technology of choice forthe wireless terminals.

The WPAN technology is led by Bluetooth that has been designed as acable replacement technology to provide device interconnection in theradius of approximately 10 meters. The Bluetooth network is organized asa piconet with a single master device and a number of slave deviceswhich are only allowed to communicate with the master. In this scheme asingle slave device selected by the master may transmit while othersmust wait for their turn. The Bluetooth physical layer (PHY) usesfrequency hopping spread spectrum (FHSS) technology. At any point intime Bluetooth signal occupies just 1 MHz of bandwidth but the centerfrequency changes up to 1600 times per second. The frequency change(hopping) pattern is selected by the piconet master such that theinterference between different piconets is minimized. A time-divisionduplex (TDD) technique is used to transmit and receive data in apiconet. The transmission channel is divided into 625us slots. Piconetmaster transmits during even-numbered slots while the slave devicestransmit during odd-numbered slots. The specification also allowsmultislot transmissions where packets occupy multiple consecutive slots(three or five). A slave must respond to the master's packet addressedto it. If it has no data it must respond with a NULL packet. TheBluetooth specification defines the following types of links for thesupport of voice and data applications: synchronous connection-oriented(SCO), extended synchronous (eSCO) and asynchronous connectionless(ACL). SCO and eSCO links are typically used for transmitting real-timevoice and multimedia packets while ACL is most often used for non-realtime data traffic. The SCO packets do not have cyclic redundancy check(CRC) protection and are never retransmitted. eSCO and ACL packets useCRC and errors are corrected by packet retransmission. The most typicalBluetooth application is found in the wireless headsets.

WLAN technologies are lead by IEEE 802.11 that defines two differentways to configure a wireless network: ad hoc mode and infrastructuremode. In ad hoc mode, nodes are brought together to form a network onthe fly, whereas infrastructure mode uses fixed access points (AP)through which mobile nodes can communicate. These network access pointsare usually connected to wired networks through bridging or routingfunctions.

The WLAN medium access control (MAC) layer is a contention-resolutionprotocol that is responsible for maintaining order in the use of ashared wireless medium. IEEE 802.11 specifies both contention-based andcontention-free channel access mechanisms. The contention-based schemeis also called the distributed coordination function (DCF) and thecontention free scheme is also called the point coordination function(PCF). The DCF employs a carrier sense multiple access with collisionavoidance (CSMA/CA) protocol. In this protocol, when the WLAN MACreceives a packet to be transmitted from its higher layer, the MAC firstlistens to ensure that no other node is transmitting. If the channel isclear, it then transmits the packet. Otherwise, it chooses a randombackoff factor that determines the amount of time the node must waituntil it is allowed to transmit its packet. During periods in which thechannel is clear, the WLAN MAC waiting to transmit decrements itsbackoff counter, and when the channel is busy, it does not decrement itsbackoff counter. When the backoff counter reaches zero, the WLAN MACtransmits the packet. Because the probability that two nodes will choosethe same backoff factor is low, collisions between packets areminimized. Collision detection, as employed in Ethernet, cannot be usedfor the radio frequency transmissions of devices following IEEE 802.11.The IEEE 802.11 nodes are half-duplex—when a node is transmitting, itcannot hear any other node in the system that is transmitting becauseits own signal drowns out any others arriving at the node.

Optionally, when a packet is to be transmitted, the transmitting nodecan first send out a short request to send (RTS) packet containinginformation on the length of the packet. If the receiving node hears theRTS, it responds with a short clear to send (CTS) packet. After thisexchange, the transmitting node sends its packet. If the packet isaddressed to a single recipient (directed packet) is receivedsuccessfully, as determined by a cyclic redundancy check (CRC), thereceiving node transmits an acknowledgment (ACK) packet. If thetransmitting node does not receive an ACK for the directed packet itassumes that the packet transmission had failed and error recovery isattempted by retrying the original packet. Retries are continued untileither the ACK packet is received or the retry limit is reached. In thelater case the packet is retried at a lower data rate and if that failsthe packet is discarded.

To maintain a reliable data connection at the highest possible data ratethe WLAN transmitter usually employs dynamic rate adaptation algorithm.Such algorithm reduces the data rate for wireless communication whennumber of unsuccessful attempts to transmit a packet reaches a certainthreshold. In an environment where the thermal noise is the only sourceof receive errors this algorithm converges to the highest data ratesupported by the wireless link. However for the cases where transmissionfailed due to the interference from a Bluetooth transceiver collocatedwith the receiving node this rate adaptation algorithm would result inlowering the data rate, increasing the packet transmission time and thusfurther increasing the probability of the interference errors.

When the packet is lost the overall network performance is affected. Theimpact is dependent on the type of packets. Discarding directed framesmight result in poor voice quality in VoIP link or lower TCP throughput.If a wireless station fails to receive multicast packets might result isfailures in such protocols as ARP and DHCP. Loosing beacon frames mightresult in loss of synchronization to the wireless network.

As WLAN and WPAN are designed for different uses they often complementeach other in personal computers and mobile devices such as phones andpersonal digital assistants. And while these two wireless systems usedifferent technologies they operate in the same 2.4 GHz ISM band and asa result interfere with each other. The problem of Bluetooth interferingwith WLAN is particularly serious when these two technologies areimplemented on a single chip and share some of the radio components.Such interference might cause degraded data throughput, reduced voicequality or even link disconnection.

The interference between WLAN and WPAN networks can be divided into twoclasses. The interference is said to be external if the interferingdevices are physically separated by a distance of more than two meters.The interference is said to be internal if the devices are located at adistance of less than two meters and devices are said to be collocated.The internal interference is much more severe as each wirelesstransceiver has drastic impact on the performance of the other, as it'stransmit/receive activity may saturate the LNA of the other device.

The mutual interference between BT and WLAN depends on several factors.The physical distance between BT and WLAN, the operating data rate,operating transmit power levels and amount of data all affect theinterference. To address the problem of mutual interference between802.11 WLAN and Bluetooth technologies IEEE has developed 802.15.2Recommended Practice that offers several coexistence mechanisms toenable WLAN and Bluetooth to operate in a shared environment withoutadversely affecting each others performance. The IEEE 802.15.2Recommended Practice categorizes coexistence mechanisms into twoclasses: collaborative and non-collaborative. The former is applicableto collocated WLAN and Bluetooth and requires exchange of informationbetween these two devices, while the later does not require informationsharing.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of ordinary skill in the artthrough comparison of such systems with the present invention.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theDrawings, the Detailed Description of the Invention, and the claims.Other features and advantages of the present invention will becomeapparent from the following detailed description of the invention madewith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a wireless communication systemin accordance with the present invention;

FIG. 2 is a schematic block diagram of a wireless communication devicein accordance with an embodiment of the present invention;

FIG. 3 is a schematic block diagram of processing modules 150 and 152 inaccordance with an embodiment of the present invention;

FIG. 4 is a schematic block diagram of processing modules 150 and 152 inaccordance with an embodiment of the present invention;

FIG. 5 is a timing diagram that illustrates an exemplary communicationof BT HV3 frames and WLAN transmissions, in accordance with anembodiment of the invention;

FIG. 6 is a timing diagram that illustrates an exemplary communicationof BT HV3 frames and WLAN transmissions, in accordance with anembodiment of the invention;

FIG. 7 is a timing diagram that illustrates an exemplary communicationof BT HV3 frames and WLAN transmissions, in accordance with anembodiment of the invention;

FIG. 8 is a schematic block diagram of a wireless interface device inaccordance with an embodiment of the present invention;

FIG. 9 is a schematic block diagram of an embodiment of an antennasection in accordance with the present invention;

FIG. 10 is a schematic block diagram of an embodiment of an antennasection in accordance with the present invention;

FIG. 11 is a timing diagram that illustrates an exemplary scheduling ofBT page scans and a WLAN beacon window, in accordance with an embodimentof the invention;

FIG. 12 is a flowchart representation of a method in accordance with anembodiment of the present invention;

FIG. 13 is a flowchart representation of a method in accordance with anembodiment of the present invention;

FIG. 14 is a flowchart representation of a method in accordance with anembodiment of the present invention;

DETAILED DESCRIPTION OF THE INVENTION

The following abbreviations are presented for clarity:

A2DP Advanced Audio Distribution Profile AP Access Point ACKAcknowledgement ACL Asynchronous Connectionless AM Active Mode AWMAAlternating Wireless Medium Access AFH Adaptive Frequency Hopping BTBluetooth BPF Band Pass Filter BSS Basic Service Set CRC CyclicRedundancy Check CS Carrier Sense CSMA/CA Carrier Sense Multiple Accesswith Collision Avoidance CTS Clear To Send DCF Distributed CoordinationFunction DTIM Delivery Traffic Indication Map ECI Enhanced CoexistenceInterface EDR Extended Data Rate eSCO Enhanced Synchronous ConnectionOriented FHSS Frequency Hopping Spread Spectrum FTP File TransferProtocol IBSS Independent Basic Service Set IGMP Internet GroupManagement Protocol ISM Industrial, Scientific and Medical LNA Low NoiseAmplifier MAC Medium Access Control NAV Network Allocation Vector PAPower Amplifier PCF Point Coordination Function PER Packet Error RatePHY Physical layer PTA Packet Transmit Arbitration PS Power Save RSSIReceived Signal Strength Indicator RTS Request To Send RX Receive SCOSynchronous Connection Oriented STA Station SIFS Short Inter Frame SpaceTDD Time-Division Duplex TDMA Time-Division Multiple Access TSSITransmit Signal Strength Indicator TPC Transmit Power Control TXTransmit UMA Unlicensed Mobile Access VoIP Voice over IP VoWLAN Voiceover WLAN WLAN Wireless Local Area Network WPAN Wireless Personal AreaNetwork

FIG. 1 is a schematic block diagram illustrating a communication system10 that includes a plurality of base stations and/or access points12-16, a plurality of wireless communication devices 18-32 and a networkhardware component 34. The wireless communication devices 18-32 may belaptop host computers 18 and 26, personal digital assistant hosts 20 and30, personal computer hosts 24 and 32, cellular telephone hosts 22 and28 and/or other wireless devices.

The base stations or access points 12-16 are operably coupled to thenetwork hardware 34 via local area network connections 36, 38 and 40.The network hardware 34, which may be a router, switch, bridge, modem,system controller, etcetera, provides a wide area network connection 42for the communication system 10. Each of the base stations or accesspoints 12-16 has an associated antenna or antenna array to communicatewith the wireless communication devices in its area. Typically, thewireless communication devices register with a particular base stationor access point 12-14 to receive services from the communication system10. For direct connections (i.e., point-to-point communications),wireless communication devices communicate directly via an allocatedchannel.

Typically, base stations are used for cellular telephone systems andlike-type systems, while access points are used for in-home orin-building wireless networks. Regardless of the particular type ofcommunication system, each wireless communication device includes abuilt-in radio and/or is coupled to a radio.

In an embodiment of the present invention, one or more of thecommunication devices 18, 20, 22, 24, 26, 28, 30 and 32 operates over anadditional wireless network, such as a wireless personal area network,that shares the same spectrum or otherwise could potentially interferewith wireless communication between the base stations or access points12, 14 and 16 and the wireless communication devices 18, 20, 22, 24, 26,28, 30 and 32. For example, the base stations or access points 12, 14and 16 could operate in accordance with a wireless local area networkprotocol such as an 802.11 protocol and one or more wirelesscommunication devices 18, 20, 22, 24, 26, 28, 30 and 32 can beBluetooth-enabled. In this case, WLAN and Bluetooth communications couldboth use the 2.4 GHz frequency band. For instance, the laptop host 18may communicate via Bluetooth technology with a keyboard, a mouse, aprinter, a mobile phone, a PDA, and/or a set of headphones or speakers,where these devices and the laptop host 18 may form an ad-hoc Bluetoothpiconet. Generally, a Bluetooth piconet may comprise a master device orterminal and up to seven slave devices or terminals. In this exemplaryimplementation, the laptop host 18 may correspond to the masterBluetooth terminal and the peripheral devices 114 may correspond to theslave Bluetooth terminals. Similarly, cell phone host 22 couldcommunicate via Bluetooth technology with a Bluetooth headset and placewireless telephone calls via a base station of wireless IP telephonecalls via an access point or base station.

The present invention is directed to power savings associated with theoperation of two or more transceivers in a single device. In addition,the wireless communication devices 18, 20, 22, 24, 26, 28, 30 caninclude one or more features of the present invention addressingcoexistence issues that will be described in greater detail withreference to FIGS. 2-18. Examples of such coexistence issues include thefollowing.

Concurrent WLAN and Bluetooth Data Connections

In this set of use cases, Bluetooth uses ACL link to move data to andfrom the collocated device while WLAN is active. The performance ismeasured in terms of throughput for each of the wireless interfaces. Thefollowing configuration permutations can be addressed:

-   -   Collocated Bluetooth device being master or slave;    -   Collocated Bluetooth device is uploading/downloading data;    -   Collocated WLAN device is uploading, downloading or providing        bi-directional data traffic at different data rates;    -   Collocated WLAN device is performing channel scan or periodic        radio calibration.

These use cases are most forgiving as both Bluetooth ACL and WLANsupport packet error detection and retransmission.

Concurrent Bluetooth Voice and WLAN Data Connections

In these use cases, Bluetooth uses SCO or eSCO link to send high qualityvoice to the wireless headset while WLAN transfers data. The Bluetoothdata is usually limited to 64 Kbps in both directions and itsperformance is measured in terms of packet error rate (PER) or voicequality score such as ITU-T P.862 (PESQ) [6]. The WLAN performance ismeasured in terms of throughput. The following configurationpermutations can be addressed:

-   -   Collocated Bluetooth device being master or slave;    -   Collocated Bluetooth device uses SCO packets (HV1, HV3);    -   Collocated Bluetooth device uses eSCO packets (EV1, EV3, EV4,        EV5, 2EV3, 2EV5, 3EV3, 3EV5);    -   Collocated WLAN device is uploading, downloading or providing        bi-directional data traffic at different data rates;    -   Collocated WLAN device is performing channel scan or periodic        radio calibration.

Concurrent Bluetooth High Quality Audio Streaming and WLAN DataConnection

The Bluetooth Advanced Audio Distribution Profile (A2DP) specifies theprotocols and procedures that realize distribution of audio content ofhigh-quality in mono or stereo on Bluetooth ACL channels. It definesvarious audio codec setting with resulting maximum data rate of 320 Kbpsfor mono and 512 Kbps for two channel devices. This use case isdifferent from Bluetooth data as the maximum jitter and the minimumthroughput requirements must be met for the Bluetooth device to avoidaudio quality deterioration. The following configuration permutationscan be addressed:

-   -   Collocated Bluetooth device being master or slave;    -   Collocated Bluetooth device is sending or receiving audio        stream;    -   Collocated WLAN device is uploading, downloading or providing        bi-directional data traffic at different data rates;    -   Collocated WLAN device is performing channel scan or periodic        radio calibration.

Concurrent Bluetooth Scan and WLAN Data Connection

In these use cases Bluetooth device performs or receives inquiry or pagescan while the WLAN transfers data. The following configurationpermutations can be addressed:

-   -   Collocated Bluetooth device is in page or inquiry state;    -   Collocated Bluetooth device is performing page or inquiry scan;    -   Collocated WLAN device is uploading, downloading or providing        bi-directional data traffic at different data rates;    -   Collocated WLAN device is performing channel scan or periodic        radio calibration.

For these cases, it is desirable for the Bluetooth scan to succeed withminimum impact on WLAN throughput, scan or calibration results.

Concurrent Voice Over WLAN (VoWLAN) and Bluetooth Voice Traffic

In these use cases, WLAN serves as a bridge between VoIP internettraffic and WLAN enabled phone while Bluetooth is used to enablewireless headset. The VoIP packets are usually contain 20 ms worth ofcompressed voice and depending on the voice codec type are 20-160 bytesin size (not counting various protocol overheads). These WLAN packetsare delivered once pr 20 ms to ensure uninterrupted voice stream. Forthese usage cases both WLAN and Bluetooth performance is measured interms of packet error rate and P.862 voice quality score. In addition asWLAN packets can be delayed packet jitter is also an important metric injudging VoWLAN system performance. The following configurationpermutations can be addressed:

-   -   Collocated Bluetooth device being master or slave;    -   Collocated Bluetooth device uses SCO packets (HV1, HV3);    -   Collocated Bluetooth device uses eSCO packets (EV1, EV3, EV4,        EV5, 2EV3, 2EV5, 3EV3, 3EV5);    -   Collocated Bluetooth device is in page or inquiry state;    -   Collocated Bluetooth device is performing page or inquiry scan;    -   Collocated WLAN device is supporting bi-directional VoWLAN        traffic at different data rates;    -   Collocated WLAN device is performing channel scan or periodic        radio calibration.        Video and Audio Streaming Over WLAN with Concurrent High Quality        Audio Bluetooth Connection

In these use cases, the WLAN interface is used for streaming real-timevideo and audio data to the mobile device and Bluetooth is used forproviding high quality audio connection to the stereo headphones. Theseare one of the most challenging use cases due to the real-time nature ofthe multimedia traffic on both interfaces and the high data ratesemployed. The following configuration permutations must be addressed:

-   -   Collocated Bluetooth device being master or slave;    -   Collocated Bluetooth device uses SCO packets (HV1, HV3);    -   Collocated Bluetooth device uses eSCO packets (EV1, EV3, EV4,        EV5, 2EV3, 2EV5, 3EV3, 3EV5);    -   Collocated Bluetooth device uses ACL with various packet types;    -   Collocated Bluetooth device is in page or inquiry state;    -   Collocated Bluetooth device is performing page or inquiry scan;    -   Collocated WLAN device is supporting one channel of video and up        to two channels of audio at different data rates.

In addition, other coexistence issues can exist in other scenarios andwith other transceivers that operate in accordance with other wirelesscommunication protocols. The discussion above is meant to beillustrative of the type of issues that can be faced by such devices andnot an exhaustive list of all coexistence issues that can be addressedwithin the broad scope of the present invention.

FIG. 2 is a schematic block diagram illustrating a wirelesscommunication device that includes the host device, or module, 18-32 andat least two wireless interface devices, or radio transceivers, 57 and59. The wireless interface devices can be wireless interface circuitsthat are implemented separately or with a single integrated circuits,built in components of the host device 18, 20, 22, 24, 26 28 30 or 32(18-32), externally coupled components or part of a common integratedcircuit that includes host device 18-32 and wireless interface devices57 & 59. As illustrated, the host device 18-32 includes a processingmodule 50, memory 52, radio interfaces 54 and 55, input interface 58 andoutput interface 56. The processing module 50 and memory 52 execute thecorresponding instructions that are typically performed by the hostdevice. For example, for a cellular telephone host device, theprocessing module 50 performs the corresponding communication functionsin accordance with a particular cellular telephone standard.

The radio interfaces 54 and 55 each communicate with a processing module150 or 152 of the corresponding wireless interface device 57 or 59.These processing modules include a media-specific access controlprotocol (MAC) layer module and other processing functionality tosupport the features and functions of the particular wireless protocolemployed by the wireless access device and further to perform additionalfunctions and features of the present invention as described herein. Theprocessing modules 150 and 152 may be implemented using a sharedprocessing device, individual processing devices, or a plurality ofprocessing devices.

The wireless interface devices 57 and 59 further include andigital-to-analog converter (DAC), an analog to digital converter (ADC),and a physical layer module (PHY). The radio interfaces 54 and 55 allowdata to be received from and sent to external devices 63 and 65 via thewireless interface devices 57 and 59. Each of the external devicesincludes its own wireless interface device for communicating with thewireless interface device of the host device. For example, the hostdevice may be personal or laptop computer, the external device 63 may bea headset, personal digital assistant, cellular telephone, printer, faxmachine, joystick, keyboard, or desktop telephone, and the secondexternal device 65 may be an access point of a wireless local areanetwork. In this example, the external device 63 would include aBluetooth wireless interface device, external device 65 would include anIEEE 802.11 wireless interface device, and the computer would includeboth types of wireless interface devices.

For data received from one of the wireless interface devices 57 or 59(e.g., inbound data), the radio interface 54 or 55 provides the data tothe processing module 50 for further processing and/or routing to theoutput interface 56. The output interface 56 provides connectivity to anoutput display device such as a display, monitor, speakers, et ceterasuch that the received data may be displayed. The radio interfaces 54and 55 also provide data from the processing module 50 to the wirelessinterface devices 57 and 59. The processing module 50 may receive theoutbound data from an input device such as a keyboard, keypad,microphone, etcetera via the input interface 58 or generate the dataitself. For data received via the input interface 58, the processingmodule 50 may perform a corresponding host function on the data and/orroute it to one of the wireless interface devices 57 or 59 via thecorresponding radio interface 54 or 55.

In operation, to mitigate interference between the two or more wirelessinterface devices 57 and 59 of the wireless communication device, theprocessing modules 150 and 152 of each wireless interface device 57 and59 communicate with each other via a high speed data bus such as bus154, to coordinate their activities. In particular, bus 154bidirectionally communicates cooperation data between the wirelessinterface devices 57 and 59, wherein the cooperation data relates tocooperate transceiving in a similar, and/or otherwise interfering orcommon frequency spectrum.

Consider, for example, the application where one of the wirelessinterface devices transceive data packets in accordance with a Bluetoothstandard while the other wireless interface devices transceives datapackets in accordance with an IEEE 802.11 standard. One of the wirelessinterface devices 57 or 59 can provide cooperation data such as anindication of receiving an inbound packet to another one of the wirelessinterface devices. The other wireless interface device processes theindication and transmits an outbound packet in accordance with theprocessing of the indication. For example, the processing may beperformed to determine when the first wireless interface device isreceiving the inbound packet. If so, the other wireless interface devicemay delay transmitting the outbound packet until the one of the wirelessinterface devices has received the inbound packet. Note that, tominimize the time that one wireless interface device is receivingpackets, and hence reduce the wait time, the packet size of inboundpackets and outbound packets may be optimized in accordance with theparticular wireless communication standard. As a further example, theprocessing of the indication may be to determine whether thetransmitting of the outbound packet would interfere with the receivingof the inbound packet. If so, the other wireless interface device maydelay transmitting the outbound packet until the one of the wirelessinterface devices has received the inbound packet. If the transmittingof the outbound packet would not interfere with the receiving of theinbound packet, the other wireless interface device transmits theoutbound packet while the inbound packet is being received. Note that toreduce interference, the wireless interface device that is compliantwith the Bluetooth standard may adaptively adjust its frequency hoppingsequence to reduce interference with the other wireless interfacedevice.

Further, the wireless interface devices 57 and 59 can operate toexchange cooperation data in the form of status messages regardingtransmission and reception of packets. Note that a status message may beprovided in response to a request from the other wireless communicationdevice for a particular piece of information, for a full status report,or any portion thereof and each of the wireless interface devicestransmits an outbound packet in accordance with the processing of thereceived status messages.

In one example of the processing of the status message and transmittingof the outbound packet, the wireless interface device determines thatthe other wireless interface device is currently receiving an inboundpacket. In this situation, the wireless interface device may delaytransmitting of the outbound packet until the other wireless interfacedevice has received the inbound packet.

In another example of the processing of the status message andtransmitting of the outbound packet, the wireless interface devicedetermines that the other wireless interface device is expecting toreceive an inbound packet. In this situation, the wireless interfacedevice may delay transmitting of the outbound packet until the otherwireless interface device has received the inbound packet unless thedelay would cause an interrupt for low latency real time transmissions.

In yet another example of the processing of the status message andtransmitting of the outbound packet, the wireless interface devicedetermines that the other wireless interface device is transmitting anoutbound message. In this situation, the wireless interface device maydelay transmitting of the outbound packet until the other wirelessinterface device has transmitted the inbound packet unless interferencewould be minimal or if a delay would cause an interrupt for low latencyreal time transmissions.

In a further example of the processing of the status message andtransmitting of the outbound packet, the wireless interface devicedetermines that the other wireless interface device is expecting totransmit another outbound message. In this situation, the wirelessinterface device randomizes the delay in transmitting the outboundpacket in accordance with a random transmission protocol. For example,each wireless interface device may be assigned a unique wait period whenthey detect that two or more wireless interface devices desire totransmit a packet at about the same time.

In an additional example, one of the wireless interface devices 57 or 59determines whether a second wireless interface device is transmitting anoutbound packet based on information shared over the bus 154. If theother wireless interface device is not transmitting, the wirelessinterface device transmits its packet. If, however, the other wirelessinterface device is transmitting a second outbound packet, the wirelessinterface device determines whether transmitting its outbound packetwould interfere with the transmitting of the second outbound packet.This may be done by comparing the transmit power level of the firstwireless interface device with the transmit power level of the secondwireless interface device. If they are similar and relatively low, theinterference may be minimal. If, however, there would be sufficientinterference, the wireless interface device delays transmitting thefirst outbound packet until the second outbound packet has beentransmitted.

Also, cooperation data can include a sleep status indicator that isasserted when a WLAN wireless interface device in idle mode wakes up tolisten for beacon and is deasserted when it goes to sleep. This can beused for synchronizing Bluetooth scan activities with the STA listeningfor and receiving beacons when both Bluetooth as well as the STA areotherwise in standby mode, thus improving power consumption in thatmode. For instance, Bluetooth would timestamp the instants when beaconlistening commences and ends and accordingly schedule page and inquiryscans to overlap.

It should be noted that implementation of bus 154 as a high-speed databus allows cooperation data to be shared between wireless interfacedevices 57 and 59 on a packet by packet basis. In particular, the bus154 can bidirectionally communicate cooperation data between theprocessing modules 150 and 152 and the second processing module for eachtransmitted or received packet of either wireless interface device 57and/or 59. Cooperation data can further include channel data, such as achannel number that identifies a selected one of a plurality ofchannels, a master/slave indicator, a signal strength indicator, anantenna status indicator, a transmit power level indicator, a currenthop frequency, a future hop frequency, a slot hop time, and a frequencyhop sequence, a voice activity detection status indicator, a transmittiming parameter, a receive timing parameter, delivery trafficindication message (DTIM) interval indicator, a station idle modeindicator, and/or other data.

In accordance with one mode of operation, the processing modules 150 and152 are implemented with separate processing devices that primarilyperform processing on the packetized data from their own respectivewireless interface devices, but are operable to perform tasks for theother processing module. In particular, each processing module isoperable to assign a processing task relating to the processing of itsown packetized data to the other processing module, via task informationcommunicated via the bus 154 or by other means. This task informationcan include a task assignment that identifies a task to be performed, atask priority that corresponds to the assigned task, and a plurality oftask data to be processed by the other processing module. Further thetask information can include a plurality of results data generated bythe other processing module in response to the task data and optionallyother control data.

In an embodiment of the present invention, the processing task can be tocompress or decompress data in accordance with a JPEG, MPEG, MP3 orother audio, video image or data compression standard or algorithm, toencrypt or decrypt data in accordance with one or more encryptionalgorithms or to perform other data processing. For instance, aprocessing module associated with a Bluetooth wireless interface devicecan perform encryption processing or other security operations for aWLAN wireless interface device in response to receiving a taskassignment via the bus 154 that identifies the particular securityoperation and task data that includes the data to be encrypted. When theBluetooth processing module has completed the task, the resulting datacan be transferred back to the WLAN processing module as results datavia the bus 154 for use by the WLAN processor in processing its ownpacketized data.

In addition, task information can include a task identifier and taskpriority that pertains to the task currently being performed by eachprocessing module 150, 152. For instance, should a processing module 150or 152 be performing a high priority realtime task for a period of time,the other processor may determine not to assign a processing task duringthis period of time.

In an embodiment, wireless interface devices 57 and 59 are implementedwith one or more shared modules that are operational in a first state,and yet can placed in a low-power state that reduces the powerconsumption of the module or shuts off the module in order to conservepower. Examples of such a shared module include a low noise amplifier,an oscillator such as a crystal oscillator or other oscillator circuit,a memory, a processing module or other module that can be used by boththe wireless interface devices 57 and 59 in operation and switched tothe low power state when not in use in order to conserve power. In onemode of operation, cooperation data is shared between the wirelessinterface devices 57 and 59 relating to cooperate use of the at leastone module.

In a mode of operation, the switching of the shared modules betweenoperational states and low power states can be coordinated bycooperation data communicated via bus 154 or other signaling path. Forinstance, one wireless interface device can indicate that it isbeginning to use a shared module, giving another wireless interfacedevice the opportunity to use the shared device at the same time.Further, one wireless interface device can indicate that it hascompleted its use of a shared module but switch to a low power state if,via cooperation data, it is determined that the other wireless interfacedevice has completed using or otherwise is not using the shared module.

In another example, activities that use the shared device can becoordinated by means of a wireless interface schedule so that uses ofthe shared module or modules is minimized. For instance, a wirelessinterface schedule can be stored in memory associated with processingmodule 150 and/or 152 that includes a first time interval wherein thefirst wireless interface device and the second wireless interface devicecontemporaneously use the at least one module in the first state and asecond time interval wherein the at least one module is in the secondstate. In applications where the wireless interface device 57 operatesin accordance with a wireless local area network protocol, such as an802.11 protocol, and wireless interface device 59 operates in accordancewith a wireless pico-net protocol such as a Bluetooth protocol, a timeinterval in the wireless interface schedule for wireless interfacedevice 57 to scan for an incoming beacon from an access point, can alsobe used for receiving Bluetooth page scans via the wireless interfacedevice 59. In particular, a low noise amplifier, oscillator or othershared module can be used simultaneously by the receivers of interfacedevices 57 and 59 to reduce the amount of time that these shared devicesare powered and/or fully powered and therefore, to reduce powerconsumption.

In an embodiment of the present invention, a Bluetooth processing module(150 or 152) is included in a Bluetooth wireless interface device (57 or59) with the other processing module being a WLAN processing module in aWLAN wireless interface device. The bus 154 includes a 96-bit parallelinterface (including 64 firmware lines and 32 hardware lines) forcommunication from the Bluetooth processing module and the WLANprocessing module an a 32-bit parallel interface for communication fromthe WLAN processing module to the Bluetooth processing module asfollows:

64-bit Bluetooth Firmware Lines

-   -   (8 bits)—Current task id that represents the current task or        packet type being processed.    -   (1 bit)—Current Master/Slave role.    -   (3 bits)—Multi-level priority. This can either be static based        on the task id or configurable so that priorities can changed        for different tasks or packet types on the fly.    -   (8 bits)—Current transmit power level    -   (8 bits)—Current RSSI (Real-time, signaled prior to every        Bluetooth transaction).    -   (1 bit)—Whether voice activity detection is being employed.    -   (5 bits)—Selectable time from an active bit being asserted high        until the time the WLAN power amp should be off.    -   (30 bits) Reserved.

32-bit Bluetooth Hardware Lines

-   -   (7 bits) Upcoming slot hop frequency.    -   (1 bit) Reset    -   (24 bits) Reserved.

32-bit WL Signal Lines

-   -   (5 bits) WLAN channel number.    -   (2 bits) Slot usage request to Bluetooth.    -   (1 bit) Shared or dual antenna configuration indicator.    -   (1 bit) Indication from WLAN to Bluetooth to force remote        Bluetooth to transmit at remote Bluetooth's maximum transmit        power possible to improve SINR at Bluetooth's receiver.    -   (2 bits) DTIM interval (i.e. 100, 300, 500 ms, etc.)    -   (1 bits) Indication from the STA that it is in idle mode, merely        listening to beacons.    -   (1 bits) Sleep status indicator    -   (19 bits) Task information, including task assignment (2 bits),        WLAN task data/results data (16 bits) and reserved.

The reserved data bits can be used to transfer other task information,including task assignment data, BT & WLAN task data/results data, othercooperation data including cooperation data relating to the cooperativeuse of one or more shared modules and/or other data. This example isillustrative of some of the many possible forms of cooperation data andtask information that can be shared between wireless interface devicesin accordance with an embodiment of the present invention. It should benoted that, while a Bluetooth and WLAN wireless interface devices 57 and59 are contemplated in this particular example, other wireless interfacedevices could likewise be implemented such as GSM, general packet radioservice (GPRS), enhanced data rates for global evolution (EDGE),universal mobile telecommunication system (UMTS), CDMA, TDMA, LMPS, orMMPS or other wireless interfaces using similar or other taskinformation and cooperation data.

FIG. 3 is a schematic block diagram of processing modules 150 and 152 inaccordance with an embodiment of the present invention. In particular,processing module 152 includes memory 350, processing engine 352 andinterface 342 that are coupled to bus 154. Processing module 150includes a logic block 366 that couples bus 154 to silicon backplane364, that is, in turn, coupled to memory 360, processing engine 362 andinterface 344. Interfaces 342 and 344 optionally provide additionalsignaling 346 between the processing modules 150 and 152 that can beoffloaded from the bus 154.

Processing engines 352 and 362 can include a microprocessor,micro-controller, digital signal processor, microcomputer, centralprocessing unit, field programmable gate array, programmable logicdevice, state machine, logic circuitry, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions that are stored in a memory.The memories 350 and 360 can each may be a single memory device or aplurality of memory devices. Such a memory device may be a read-onlymemory, random access memory, volatile memory, non-volatile memory,static memory, dynamic memory, flash memory, and/or any device thatstores digital information. Note that when the processing engines 352and/or 362 implements one or more of its functions via a state machine,analog circuitry, digital circuitry, and/or logic circuitry, the memorystoring the corresponding operational instructions is embedded with thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry.

FIG. 4 is a schematic block diagram of processing modules 150 and 152 inaccordance with an embodiment of the present invention. In particular,additional signal lines 346 can be employed to provide additionalcooperation data such as additional control and scheduling informationbetween the wireless interface devices 57 and 59. These addition signals346 can support IEEE 802.15.2 and/or provide additional signaling.

Addt'l sig. 346 Description Medium Request 330 Asserted to request touse the medium. Priority status 332 Signals Bluetooth priority status.BT transmit 334 Indicates that Bluetooth has started transmitting dataBT receive 336 Indicates that Bluetooth has started receiving a validframe Medium grant 338 Medium access confirmation; permission to receiveor transmit. RF controls 340 Signals to control various RF switchesincluding antenna switch, shared LNA gain, or other RF control

In an embodiment of the present invention, Packet Transmit Arbitration(PTA) operates via the WLAN processing module 150 within MAC layerprocessing. The PTA provides per packet authorization of alltransmissions talking place between collocated WLAN and Bluetoothdevices. Bluetooth device requests medium access authorization from PTA,which may either allow or deny the requests depending on the status ofthe WLAN device. WLAN programs PTA into one of the following foursettings:

-   -   PTA grants all Bluetooth medium requests;    -   PTA grants high priority Bluetooth requests only. (Priority        status 332 is asserted at the time when medium request 330 is        asserted);    -   PTA grants high and medium priority Bluetooth requests.        (Priority status 332 signal is asserted or BT receive 336 signal        is asserted at the time when medium request 330 is asserted);    -   PTA does not grant any Bluetooth medium requests.

The PTA setting can be changed dynamically by the WLAN processing module150 device and can be configured to be dependent on the WLAN activity atthe time of the request.

In an embodiment of the present invention, these signal lines can bebidirectional, particularly when shared coexistence decisions are madebetween processing modules 150 and 152.

While shown as separate signals lines, additional signaling 346 can beincluded in the cooperation data shared via bus 154, such as byutilizing one or more additional bits or by using one or more reservedbits. Alternatively these signals can be provided by other signal pathsbetween the wireless interface devices 57 and 59. Other signaling, notshown, can likewise be included such as a restricted frequency indicatorthat is asserted when the wireless interface device 59 is about totransmit on a restricted channel.

FIG. 5 is a timing diagram that illustrates an exemplary communicationof BT HV3 frames and WLAN transmissions, in accordance with anembodiment of the invention. In this embodiment, the wireless interfacedevice 57 operates in accordance with a WLAN protocol such as 802.11(a),(b), (g) or (n) or another WLAN protocol and the wireless interfacedevice 59 operates to communicate Bluetooth packets supported by thesynchronous connection-oriented (SCO) logical transport protocol, suchas Bluetooth (BT) HV3 packets. A BT HV3 packet may be generally used for64 kb/s speech transmission but need not be so limited. The BT HV3packet may comprise 30 information bytes with a payload length of 240bits and no payload header present. The bytes are not protected byforward error correction (FEC) and no cyclic redundancy check (CRC) ispresent. Because retransmission of BT HV3 packets is not supported, whena BT HV3 packet is not received, the quality of the overall transmissionis reduced since the information contained in the lost BT HV3 packetwill not be retransmitted. As a result, BT HV3 packets may require ahigher priority of transmission to avoid interference with WLANtransmission.

The transmission of a pair of BT HV3 packets between a station orterminal such as host device 18-32, and a peripheral device is referredto as a BT HV3 frame. In an embodiment of the present invention, thehost device determines or is otherwise provided a wireless interfaceschedule that allocates communication to either the wireless interfacedevices 57 or 59 during the time slots f(i). For instance BT HV3 packet302 may be transmitted from the host device to the peripheral device intime slot f(k) and a packet 304 may be transmitted from the peripheraldevice to the host device in time slot f(k+1). A time slot in Bluetoothcommunication is 625 μs in duration and may correspond to a differentfrequency in an adaptive frequency hopping (AFH) hopping sequence. A BTHV3 frame is 1.25 ms in duration. Time slots may be set aside forwireless interface device 59 at regular intervals such as every sixthtime slot or every third BT HV3 frame for transmission of BT HV3 packetsfrom the host device 18-32. For example, a first packet may betransmitted from the host device 18-32 during time slot f(k) and a nextpacket may be transmitted from the host device during time slot f(k+6).Similarly, a first packet may be received by the host device 18-32during time slot f(k+1) and a next packet may be received by the hostdevice during time slot f(k+7). As a result, no Bluetooth communicationoccurs over a period of two BT HV3 frames providing a WLAN transmissionwindow of 2.5 ms.

As shown, the TX_BT signal 305, such as the BT transmit signal 334, maybe asserted during time slots f(k) and f(k+1) and during time slotsf(k+6) and f(k+7) and provided via bus 154 to the wireless interfacedevice 57 and particularly the processing module 150 as cooperation datato establish priority transmission for the BT HV3 packets. Asserting theTX_BT signal 305 may, for example, generally disable WLAN transmissionsby the wireless interface device 57 for that 1.25 ms time interval timeinterval. The WLAN transmission window 307 illustrates an interval oftime between assertions of the TX_BT signal 306 when the wirelessinterface device 57 may transmit WLAN packets. In this example, thewireless interface device 57 may transmit WLAN packets 306 and receiveacknowledgement packets 308 during time slots f(k+2) through f(k+5) andduring time slots f(k+8) through f(k+11) as shown. It should be notedthat the timing and time duration of these packets can vary based on thepacket size and based on the data rate that is employed and that thesepackets are not drawn to scale from a timing perspective and are meant,rather, to illustrate the juxtaposition of these packets with respect toeach other and with respect to the BT and WLAN time interval set forthherein.

In the example presented above, BT HV3 packets are employed, however,when a BT wireless interface device 59 is implemented, other packetformats such as eSCO, A2DP, MP3, etc, could likewise be used in asimilar fashion.

While the wireless interface schedule described above controls thetiming of transmissions by the wireless interfaces devices 57 and 59,WLAN packets directed to wireless interface device could nevertheless bereceived from the base station or access point during the time intervalallocated for a BT frame, for instance, WLAN packet 310 that is shown.If this packet is not acknowledged by wireless interface device 57, itwill be retransmitted and could result in the lowering of the data rate.

In an embodiment of the present invention the wireless interface device57 transmits an acknowledgement packet 312 at a reduced power leveland/or reduced data rate during the BT time interval, such as thereceive period shown. In particular, the power level of the transmissioncan be reduced from the power level used by the wireless interfacedevice 57 during the WLAN time interval to reduce the interferencebetween the transmission of the acknowledgement packet 312 by thewireless interface device 57 and possible contemporaneous reception bywireless interface device 59. The data rate of the transmission can alsobe reduced from the data rate to the lowest data rate allowed by thespecification that governs communication or other data rate that islower than the data rate used by the wireless interface device 57 duringthe WLAN time interval. This lowering of the data rate increases theprobability that the acknowledgement packet 312 will be received by thebase station or access point at the reduced power level and in thepresence of possible BT interference.

In some instances, one or another of the wireless interface devices 57or 59 may not be in operation and the host device may not need tooperate in a coexistence mode that that allocates separate timeintervals for use by these wireless interface devices. In thesecircumstances, the wireless interface schedule can be determined basedon a use status of the wireless interface devices 57 and 59, allocatingall of the time slots to the wireless interface device 57 if thewireless interface device 59 is not in use and allocating the all of thetime slots to the wireless interface device 59 if the wireless interfacedevice 57 is not in use.

In addition to the role played by priority information in the assignmentof tasks from one wireless interface device to the other, priorityinformation can be shared and used for cooperative and schedulingpurposes. For instance, one or another of the wireless interface devicesmay set its own priority settings based on the tasks that the wirelessinterface desires to perform or is currently performing. For instance,the wireless interface device 57 may establish a priority setting thatonly grants permission to transmit to the wireless interface device 59for high priority BT requests, that grants all requests, that grantsmedium and high priority request or that grants no requests. This allowsone or another of the wireless interface devices (in this case the WLANradio), to control potential conflict situations based on the priorityof the activities that it wishes to accomplish and the activities thatthe other wireless interface device wishes to accomplish.

FIG. 6 is a timing diagram that illustrates an exemplary communicationof BT HV3 frames and WLAN transmissions, in accordance with anembodiment of the invention. In particular, one possible preemption modeis illustrated that uses a standard defined self clear to send featureto protect BT transmissions.

The IEEE 802.11 standard allows WLAN device to send CTS packetsaddressed to itself (CTS2SELF). These packets specify the duration fieldthat is used by all WLAN nodes to update their network allocation vector(NAV) used in virtual carrier sense (CS) mechanism. If a collocated WLANdevice sends a CTS2SELF packet addressed to itself just before Bluetoothactivity slot with duration field set to be greater or equal to theduration of the upcoming Bluetooth transaction, then all WLAN trafficwould be preempted during Bluetooth activity. This approach prevents thetransmission of all WLAN traffic including beacons from any WLAN device.It does not require the WLAN AP to do any special queuing of the WLANpackets and is compatible with any AP implementation. This approach canalso be used to delay beacon and multicast packet transmission untilafter a collocated Bluetooth device transaction. The drawback of thisscheme is that the use of NAV to protect BT activity also denies themedium to all WLAN nodes. In a congested WLAN network just a fewcollocated WLAN/Bluetooth devices employing this method cansignificantly decrease WLAN throughput.

FIG. 6 demonstrates an example of the use of CTS2SELF scheme to protecta Bluetooth HV3 SCO link. The Bluetooth device (in this case, wirelessinterface device 59) informs the WLAN device (in this case wirelessinterface device 57) that there is a HV3 data transfer at the beginningof slot f(k), such as by asserting a Medium request 330. The WLAN deviceis informed via bus 154 about the duration of the upcoming HV3 traffic(which is 1.25 ms). The WLAN device then prepares the CTS2SELF frame 314with the duration set to 1.25 ms and transmits it. A successfultransmission of CTS2SELF frame 314 prevents any WLAN activity for 1.25ms, enough for the Bluetooth to complete the transaction. The mediumbecomes free once the BT activity is over and WLAN devices can use themedium until the next Bluetooth slot (approximately 2.5 ms later). Thenthe entire cycle can be repeated.

FIG. 7 is a timing diagram that illustrates an exemplary communicationof BT HV3 frames and WLAN transmissions, in accordance with anembodiment of the invention. In particular, another possible preemptionmode is illustrated that uses a standard defined power save feature toprotect BT transmissions.

IEEE 802.11 defines two different power states for the WLAN station(STA):

-   -   Awake: STA is fully powered.    -   Doze: STA is not able to transmit or receive.        And in turn, two power management modes:    -   Active Mode (AM): STA may receive packets at any time    -   Power Save Mode (PS): STA listens to selected beacons and polls        AP for the packets if the most recent beacon indicates that AP        has buffered traffic directed for that STA

The WLAN STA informs the AP of the change in the Power Management modethrough a frame exchange using a Power Management bit in the FrameControl field. When the WLAN device is in PS mode, the AP buffers allthe traffic directed to that device until it either switches to ActiveMode or polls for the buffered packets. The WLAN power managementprotocol can be used effectively to mitigate Bluetooth interference. Thebiggest advantage of this method is that does not inhibit other WLANnodes from communicating and thus works well even in the congested WLANenvironment. The main drawback is that the traffic buffering overhead inthe WLAN AP can cause WLAN throughput degradation.

In the embodiment shown in FIG. 7, the collocated WLAN device transmitsa frame 316 indicating to the access point that the WLAN device isentering PS mode. The WLAN device remains is PS mode indefinitely anduses PS-POLL frames 317 to poll the buffered data from the AP. The WLANMAC transmits a PS-POLL frame, for instance when the medium request 330is de-asserted, in expectation that the AP would send the buffered databefore the start of the next Bluetooth transaction. As the type ofBluetooth traffic is available via bus 154 the WLAN knows the time ofthe next Bluetooth transaction and can determine if the AP would be ableto respond before the next Bluetooth activity cycle. But since the APresponse time for PS-POLL is not deterministic there is always a chancethat the polled WLAN packet would collide with the Bluetoothtransaction. Also the polling for every buffered packet significantlyreduces the WLAN throughput. The advantages of this approach however isthat no WLAN packet needs to be sent in the short period of timepreceding Bluetooth transaction.

Several alternatives to this preemption mode exist. For instance, thecollocated WLAN device can switch to AM after Bluetooth transaction iscompleted. The WLAN MAC can transmit a frame indicating PS mode when themedium request 330 is asserted and the frame indicating AM mode when themedium request 330 is de-asserted. The advantages of this scheme is thatAP is positively inhibited from transmitting directed packets duringBluetooth transactions and no polling is required for retrievingbuffered data, however power mode switching transactions take away fromthe available bandwidth even when there is no directed trafficavailable. In a further embodiment, a trigger frame can be used by theWLAN device to poll for all data frames buffered in the AP instead ofindividual polling using PS-POLL. This scheme is more efficient inmedium utilization but has the higher risk of the polled train ofpackets transmitted by the AP colliding with the Bluetooth transaction.

In operation, a processing module, for instance the PTA of processingmodule 150 or 152 selectively preempts use of the frequency spectrum byan external device using a plurality of preemption modes including afirst preemption mode and a second preemption mode. As discussed above,one preemption mode can preempt the use of the spectrum by an externaldevice by transmitting packetized data to the second external devicethat includes a power save mode indication. A second preemption mode canpreempt use of the spectrum by an external device by transmittingpacketized data to the second external device that includes a self clearto send indication. Other preemption modes can be employed as well. Theprocessing module is capable of switching between preemption modes basedon observed or anticipated conditions in an attempt to increasethroughput, reduce congestion, and/or prevent hogging of the channel byone of the wireless interface devices or the other or by an externaldevice.

In an embodiment of the present invention, the processing module isfurther operable to monitor a throughput associated with the secondwireless interface circuit, to compare the throughput to a throughputthreshold, and to switch from the second preemption mode to the firstpreemption mode when the throughput compares unfavorably to thethroughput threshold. For instance, while the CTS2SELF preemption modecan provide the best WLAN throughput, it can also inhibit all WLANtraffic during Bluetooth transaction. To avoid inefficient use of WLANbandwidth, the processing module constantly monitors the throughput forthe directed traffic. If the throughput falls below a threshold, theWLAN device can switch to the Power Save preemption mode. Further, theprocessing module 57 can be further operable to periodically switch fromthe first preemption mode to the second preemption mode and/or switchback from the first preemption mode to the second preemption mode. Forinstance, while in Power Save preemption mode, the WLAN device canperiodically switch to CTS2SELF protection mode to check if the volumeof the directed traffic justifies using CTS2SELF mode.

In an embodiment of the present invention, the processing module isfurther operable to determine when a third external device is using thesecond preemptive mode to limit the use of the second preemptive modewhen the third external device is using the second preemptive mode. Forinstance, Power Save preemption mode can be set as the default. If theCTS2SELF preemption mode is employed by several devices in the samenetwork, it may severely limit the network bandwidth. To prevent thisfrom happening the collocated WLAN device can monitor the medium todetermine if other devices are using CTS2SELF. The switch to CTS2SELFprotection mode can be inhibited if the device determines that theconsiderable amount of bandwidth is already used by another device ordevices using CTS2SELF.

Short of inhibiting CTS2SELF preemption mode, its use, or the use ofother preemption modes can be limited by switching preemptive modes whena time in a particular preemptive mode is exceeded, allowing a backafter a back-off period is satisfied. For instance, to prevent a singledevice from monopolizing the medium each WLAN device switches back toPower Save protection method after using CTS2SELF for a period of time.A congestion sense with random backoff (not to be confused with carriersense) is used to determine when it can switch back to CTS2SELF method.

In an embodiment of the present invention, the processing module isfurther operable to use the first preemptive mode to protect a firsttype of packetized data transceived by the first wireless interfacecircuit and to use the second preemptive mode to protect a second typeof packetized data transceived by the first wireless interface circuit.For instance, the CTS2SELF preemption mode may be limited to protectBluetooth traffic of short duration. The page and inquiry scans can beprotected by the Power Save preemption mode.

In an embodiment, the processing module is further operable to use thefirst preemptive mode to protect a first type of packetized datatransceived by the second wireless interface circuit. For instance, whenthe WLAN STA is in Power Save preemption mode it is still expected toreceive DTIM beacons and subsequent multicast traffic. If the collocatedWLAN device is using Power Save protection, it can switch to CTS2SELFprotection around DTIM beacon time to protect these WLAN transmissions.

As previously discussed, a data path, such as the bus 154 or othercommunication path can bidirectionally communicate cooperation databetween the first wireless interface circuit and the second wirelessinterface circuit. In an embodiment of the present invention thecooperation data is communicated to prevent the first wireless interfacecircuit from interfering with a beacon interval of the secondcommunication protocol. For instance, in a congested network withmultiple collocated WLAN/Bluetooth devices, not all devices will havethe opportunity to access the medium to send a CTS2SELF packet. If thedevice is unable to send a CTS2SELF packet to protect a Bluetoothtransaction around a DTIM beacon interval it may deny Bluetooth mediumaccess to the collocated wireless interface device, such as by denying amedium request 330, to prevent loosing the beacon.

In an embodiment of the present invention, the cooperation data includespriority data associated with at least one task and wherein theprocessing module is further operable to monitor a throughput associatedwith at least one of one of the first wireless interface circuit and thesecond wireless interface circuit, to compare the throughput to athroughput threshold and to modify the priority data associated with theat least one task when the throughput compares unfavorably to thethroughput threshold. For instance, in cases where both WLAN device andBluetooth device could occupy close to 100% of the available mediumbandwidth (such is the case for the concurrent WLAN and Bluetooth ACLdata connections) the respective bandwidth allocation is handled bymulti-level priority communicated from Bluetooth to WLAN over bus 154.For a particular connection, both devices maintain the data throughputtargets as well as minimum acceptable throughput requirements. As theBluetooth traffic is being held back by the PTA not granting mediumrequests and its throughput falls below the target, the Bluetooth devicecan gradually increase its multi-level priority for the upcomingtransaction opportunity. This priority is then compared with anequivalent WLAN multi-level priority to ensure fair bandwidthallocation.

FIG. 8 is a schematic block diagram of the wireless interface devices(i.e., a radio) 57 or 59, where each device includes a host interface62, digital receiver processing module 64, an analog-to-digitalconverter (ADC) 66, a filtering/attenuation module 68, an IF mixing downconversion stage 70, a receiver filter 71, a low noise amplifier 72, atransmitter/receiver switch 73, a local oscillation module 74, memory75, a digital transmitter processing module 76, a digital-to-analogconverter (DAC) 78, a filtering/gain module 80, an IF mixing upconversion stage 82, a power amplifier 84, and a transmitter filtermodule 85. The transmitter/receiver switch 73 is coupled to the antennasection 61, which may include a shared antenna 86 and an antenna switch87 (as shown in FIG. 9) that is shared by the two wireless interfacedevices and is further shared by the transmit and receive paths asregulated by the Tx/Rx switch 73. Alternatively, the antenna section 61may include separate antennas for each wireless interface device, wherethe transmit path and receive path of each wireless interface deviceshares an antenna. Still further, the antenna section 61 may include aseparate antenna for the transmit path and the receive path of eachwireless interface device. As one of average skill in the art willappreciate, the antenna(s) may be polarized, directional, and bephysically separated to provide a minimal amount of interference.

Returning to the discussion of FIG. 2, the digital receiver processingmodule 64 the digital transmitter processing module 76, and the memory75 may be included in the processing module 150 or 152 and executedigital receiver functions and digital transmitter functions inaccordance with a particular wireless communication standard. Thedigital receiver functions include, but are not limited to, digitalintermediate frequency to baseband conversion, demodulation,constellation demapping, decoding, and/or descrambling. The digitaltransmitter functions include, but are not limited to, scrambling,encoding, constellation mapping, modulation, and/or digital baseband toIF conversion. The digital receiver and transmitter processing modules64 and 76 may be implemented using a shared processing device,individual processing devices, or a plurality of processing devices.Such a processing device may be a microprocessor, micro-controller,digital signal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on operationalinstructions. The memory 75 may be a single memory device or a pluralityof memory devices. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, and/or any device that storesdigital information. Note that when the processing module 64 and/or 76implements one or more of its functions via a state machine, analogcircuitry, digital circuitry, and/or logic circuitry, the memory storingthe corresponding operational instructions is embedded with thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry.

In operation, the wireless interface device 57 or 59 receives outbounddata 94 from the host device via the host interface 62. The hostinterface 62 routes the outbound data 94 to the digital transmitterprocessing module 76, which processes the outbound data 94 in accordancewith a particular wireless communication standard (e.g., IEEE 802.11including all current and future subsections, Bluetooth, etcetera) toproduce digital transmission formatted data 96. The digital transmissionformatted data 96 will be a digital base-band signal or a digital low IFsignal, where the low IF typically will be in the frequency range of onehundred kilohertz to a few megahertz.

The digital-to-analog converter 78 converts the digital transmissionformatted data 96 from the digital domain to the analog domain. Thefiltering/gain module 80 filters and/or adjusts the gain of the analogsignal prior to providing it to the IF mixing stage 82. The IF mixingstage 82 directly converts the analog baseband or low IF signal into anRF signal based on a transmitter local oscillation 83 provided by localoscillation module 74. The power amplifier 84 amplifies the RF signal toproduce outbound RF signal 98, which is filtered by the transmitterfilter module 85. The antenna section 61 transmits the outbound RFsignal 98 to a targeted device such as a base station, an access point,peripheral and/or another wireless communication device.

In an embodiment of the present invention, the digital transmitterprocessing module 76 generates a control signal 156 that adjusts thegain of the power amplifier 84 so that the output power of the outboundRF signal can be raised or lowered based on the signal path loss,transmission mode and further as discussed in conjunction with FIG. 3when a packet is transmitted during a time interval of the otherwireless interface device. It should be noted that, based on theimplementation of the antenna switch 87, the gain of the power amplifier84 may need to be further adjusted to compensate for the loss associatedwith the antenna switch 87. For instance, when the antenna switch isswitched to provide coupling to wireless interface device 59 andwireless interface device needs to transmit, such as the acknowledgementpacket discussed in conjunction with FIG. 3, an additional path loss of20 dB or more may be induced by the switch being coupled to the otherwireless interface device. This additional path loss should beconsidered in this implementation in determining the gain required ofpower amplifier 84 to produce the desired reduced power leveltransmission. Of course, in other implementations with dedicatedantennas for each of the wireless interface devices 57 and 59, thisadditional loss could be eliminated.

The wireless interface device 57 or 59 also receives an inbound RFsignal 88 via the antenna section 61, which was transmitted by a basestation, an access point, or another wireless communication device. Theantenna section 61 provides the inbound RF signal 88 to the receiverfilter module 71 via the Tx/Rx switch 73, where the Rx filter 71bandpass filters the inbound RF signal 88. The Rx filter 71 provides thefiltered RF signal to low noise amplifier 72, which amplifies the signal88 to produce an amplified inbound RF signal. The low noise amplifier 72provides the amplified inbound RF signal to the IF mixing module 70,which directly converts the amplified inbound RF signal into an inboundlow IF signal or baseband signal based on a receiver local oscillation81 provided by local oscillation module 74. The down conversion module70 provides the inbound low IF signal or baseband signal to thefiltering/gain module 68. The filtering/gain module 68 filters and/orgains the inbound low IF signal or the inbound baseband signal toproduce a filtered inbound signal.

The analog-to-digital converter 66 converts the filtered inbound signalfrom the analog domain to the digital domain to produce digitalreception formatted data 90. The digital receiver processing module 64decodes, descrambles, demaps, and/or demodulates the digital receptionformatted data 90 to recapture inbound data 92 in accordance with theparticular wireless communication standard being implemented by wirelessinterface device. The host interface 62 provides the recaptured inbounddata 92 to the host device 18-32 via the radio interface 54.

While FIG. 8 shows the wireless interface devices 57 and 59 as beingimplemented with separate components, one or more modules or componentsof these devices can be implemented with shared components that operatefor both wireless interface devices. For instance, a single LNA 72 andRX filter module 71 can be used by wireless interface devices 57 and 59to filter and amplify inbound RF signals, a single reference oscillator,such as a crystal oscillator, can be used in local oscillation modules74 of both wireless interface devices as the basis for generatingseparate local oscillation signals 81 and 83, etcetera. As discussed inconjunction with FIG. 2, the shared use of these devices can becoordinated to reduce power consumption, such as by schedulingconcurrent use of these shared devices wherever possible, and by placingthese devices in a low-power state when not in use. In particular,digital receiver processing module 64 generates control signals 77 toselectively switch shared modules, in this instance LNA 72 and localoscillation module 74 or portions thereof into a low-powered state whennot in use. While control signals 77 are shown as being generated bydigital receiver processing module 64, other processing modules of thehost device could likewise be used for this purpose.

FIG. 10 is a schematic block diagram of an embodiment of an antennasection in accordance with the present invention. In this embodiment, aWLAN device, such as wireless interface device 57 includes two poweramplifiers 384 and 384′ and two LNAs 372 and 372′ for transmitting andreceiving on two frequency bands. LNA 372′, such as wireless interfacedevice 59, that also includes its own power amplifier 384″. Though notexpressly shown, the gain of LNA 372′ can be controlled to accommodateuse in either of the two wireless interface device 57 or 59 via RFcontrol 340. In addition, RF control 340 can be used to control theswitches the couple the antenna 86, through diplexer 374 and bandpassfilters 380 or 382 to the appropriate radio input or output.

FIG. 11 is a timing diagram that illustrates an exemplary scheduling ofBT page scans and a WLAN beacon window, in accordance with an embodimentof the invention. In particular, a plurality of Bluetooth page scans 392of wireless interface device 59 are scheduled during a 100 microsecondWLAN beacon window of wireless interface device 57. By performing thesepage scans during the period which wireless interface device islistening for a beacon from an access point, shared modules used inreceiving such as LNA 72, local oscillator module 74 and/or other sharedcomponents can be used for both purposes while powered and potentiallycan be placed in an unpowered or other low-power state for longer periodduring other intervals of time reducing the power consumption of thehost device. While this timing diagram illustrates the use of thepresent invention during a contemporaneous receive interval, the presentinvention can also be used to schedule contemporaneous use of sharedmodules in combined RX/TX modes, TX/TX modes and other modes ofoperation.

FIG. 12 is a flowchart representation of a method in accordance with thepresent invention. In particular a method is presented for use inconjunction with one or more functions and features described inconjunction with FIGS. 1-11. In step 500, packetized data is transceivedbetween a host module and a first external device in accordance with afirst wireless communication protocol, using a first wireless interfacecircuit. In step 502, packetized data is transceived between the hostmodule and a second external device in accordance with a second wirelesscommunication protocol using a second wireless interface circuit thatincludes at least one module that is shared with first wirelessinterface module, the at least one module having a first state where theat least one module is operational and a second state corresponding to alow-power state. In step 504 a first time interval is scheduled whereinthe first wireless interface device and the second wireless interfacedevice contemporaneously use the at least one module. In step 506, theat least one module is switched to the second state during a second timeinterval.

In an embodiment of the present invention, the first wireless local areanetwork protocol includes an 802.11 protocol, and the first wirelessinterface circuit scans for an incoming beacon during the first timeinterval. The second wireless local area network protocol can include awireless pico-network protocol and the second wireless interface circuitcan performs a page scan during the first time interval. The sharedmodule can include an oscillator, a low noise amplifier and/or othershared module.

FIG. 13 is a flowchart representation of a method in accordance with thepresent invention. In particular a method is presented for use inconjunction with one or more functions and features described inconjunction with FIG. 12. In step 510 cooperation data isbidirectionally communicated between the first wireless interfacecircuit and the second wireless interface circuit, wherein thecooperation data relates to cooperate use of the at least one module.

FIG. 14 is a flowchart representation of a method in accordance with thepresent invention. In particular a method is presented for use inconjunction with one or more functions and features described inconjunction with FIGS. 12 and 13. In step 520, a wireless interfaceschedule is generated.

It should be noted that while the preceding description focuses onembodiments wherein two wireless interface circuits share the use of oneor more modules, a communication device having three or more wirelessinterface circuits can share the use of one or more modules in a similarfashion. For example, active states of a low noise amplifier, crystaloscillator can be synchronized between BT, WLAN and Cellular (such asGSM) receivers when all three circuits are receiving, such as in standbymodes of operation.

As one of average skill in the art will appreciate, the wirelesscommunication device of FIG. 2 may be implemented using one or moreintegrated circuits. For example, the host device may be implemented onone integrated circuit, the digital receiver processing module 64, thedigital transmitter processing module 76 and memory 75 of the wirelessinterface devices 57 and 59 may be implemented on a second integratedcircuit, and the remaining components of the wireless interface devices57 and 59, less the antennas 86, may be implemented on a thirdintegrated circuit. As an alternate example, the radio 60 may beimplemented on a single integrated circuit. As yet another example, theprocessing module 50 of the host device and the digital receiver andtransmitter processing modules 64 and 76 may be a common processingdevice implemented on a single integrated circuit. Further, the memory52 and memory 75 may be implemented on a single integrated circuitand/or on the same integrated circuit as the common processing modulesof processing module 50 and the digital receiver and transmitterprocessing module 64 and 76.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “coupled to” and/or “coupling” and/or includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for indirect coupling, theintervening item does not modify the information of a signal but mayadjust its current level, voltage level, and/or power level. As mayfurther be used herein, inferred coupling (i.e., where one element iscoupled to another element by inference) includes direct and indirectcoupling between two items in the same manner as “coupled to”. As mayeven further be used herein, the term “operable to” indicates that anitem includes one or more of power connections, input(s), output(s),etc., to perform one or more its corresponding functions and may furtherinclude inferred coupling to one or more other items. As may stillfurther be used herein, the term “associated with”, includes directand/or indirect coupling of separate items and/or one item beingembedded within another item. As may be used herein, the term “comparesfavorably”, indicates that a comparison between two or more items,signals, etc., provides a desired relationship. For example, when thedesired relationship is that signal 1 has a greater magnitude thansignal 2, a favorable comparison may be achieved when the magnitude ofsignal 1 is greater than that of signal 2 or when the magnitude ofsignal 2 is less than that of signal 1.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention. One of average skill in the art will also recognize that thefunctional building blocks, and other illustrative blocks, modules andcomponents herein, can be implemented as illustrated or by discretecomponents, application specific integrated circuits, processorsexecuting appropriate software and the like or any combination thereof.

The preceding discussion has presented a method and apparatus forcooperative transceiving between wireless interface devices of a hostdevice. By enabling the wireless interface devices to communicatedirectly with each other, interference between them may be reducedand/or avoided. As one of average skill in the art will appreciate,other embodiments may be derived from the teachings of the presentinvention without deviating from the scope of the claims.

1. A circuit comprises: a first wireless interface circuit thatcommunicates packetized data to a first external device in accordancewith a first wireless communication protocol; a second wirelessinterface circuit that communicates packetized data to a second externaldevice in accordance with a second wireless communication protocol,wherein the second wireless interface circuit includes at least onemodule that is shared with first wireless interface circuit, the atleast one module having a first state where the at least one module isoperational and a second state corresponding to a low-power state; and aplurality of signal lines, coupled to the first wireless interfacecircuit and the second wireless interface circuit, that communicatecooperation data between the first wireless interface circuit and thesecond wireless interface circuit, wherein the cooperation data relatesto cooperate use of the at least one module.
 2. The circuit of claim 1wherein the first wireless interface circuit and the second wirelessinterface circuit operate in accordance with a wireless interfaceschedule that includes a first time interval wherein the first wirelessinterface device and the second wireless interface devicecontemporaneously use the at least one module in the first state and asecond time interval wherein the at least one module is in the secondstate.
 3. The circuit of claim 2 wherein the first wirelesscommunication protocol includes an 802.11 protocol, and wherein thefirst wireless interface circuit scans for an incoming beacon during thefirst time interval.
 4. The circuit of claim 2 wherein the secondwireless communication protocol includes a wireless pico-networkprotocol and the second wireless interface circuit performs a page scanduring the first time interval.
 5. The circuit of claim 1 furthercomprising: a processing module, coupled to the first wireless interfacedevice and the second wireless interface device, that generates thewireless interface schedule.
 6. The circuit of claim 1 wherein the atleast one module includes at least one of, an oscillator, and a lownoise amplifier.
 7. The circuit of claim 1 wherein the at least onemodule is powered off during the second time interval.
 8. A circuitcomprises: a first wireless interface circuit that communicatespacketized data to a first external device in accordance with a firstwireless communication protocol; a second wireless interface circuitthat communicates packetized data to a second external device inaccordance with a second wireless communication protocol, wherein thesecond wireless interface circuit includes at least one module that isshared with first wireless interface circuit, the at least one modulehaving a first state where the at least one module is operational and asecond state corresponding to a low-power state; and wherein the firstwireless interface circuit and the second wireless interface circuitoperate in accordance with a wireless interface schedule that includes afirst time interval wherein the first wireless interface device and thesecond wireless interface device contemporaneously use the at least onemodule in the first state and a second time interval wherein the atleast one module is in the second state.
 9. The circuit of claim 8wherein the first wireless communication protocol includes an 802.11protocol, and wherein the first wireless interface circuit scans for anincoming beacon during the first time interval.
 10. The circuit of claim8 wherein the second wireless communication protocol includes a wirelesspico-network protocol and the second wireless interface circuit performsa page scan during the first time interval.
 11. The circuit of claim 8wherein the at least one module includes at least one of, an oscillator,and a low noise amplifier.
 12. The circuit of claim 8 furthercomprising: a plurality of signal lines, coupled to the first wirelessinterface circuit and the second wireless interface circuit, thatcommunicate cooperation data between the first wireless interfacecircuit and the second wireless interface circuit, wherein thecooperation data relates to cooperate use of the at least one module.13. The circuit of claim 8 further comprising: a processing module,coupled to the first wireless interface device and the second wirelessinterface device, that generates the wireless interface schedule. 14.The circuit of claim 8 wherein the at least one module is powered offduring the second time interval.
 15. A method comprising: communicatingpacketized data to a first external device in accordance with a firstwireless communication protocol, using a first wireless interfacecircuit; communicating packetized data to a second external device inaccordance with a second wireless communication protocol using a secondwireless interface circuit that includes at least one module that isshared with first wireless interface module, the at least one modulehaving a first state where the at least one module is operational and asecond state corresponding to a low-power state; scheduling a first timeinterval wherein the first wireless interface device and the secondwireless interface device contemporaneously use the at least one module;and switching the at least one module to the second state during asecond time interval.
 16. The method of claim 15 wherein the firstwireless communication protocol includes an 802.11 protocol, and whereinthe first wireless interface circuit scans for an incoming beacon duringthe first time interval.
 17. The method of claim 15 wherein the secondwireless communication protocol includes a wireless pico-networkprotocol and the second wireless interface circuit performs a page scanduring the first time interval.
 18. The method of claim 15 wherein theat least one module includes at least one of, an oscillator, and a lownoise amplifier.
 19. The method of claim 15 further comprising:communicating cooperation data between the first wireless interfacecircuit and the second wireless interface circuit, wherein thecooperation data relates to cooperate use of the at least one module.20. The method of claim 15 further comprising: generating the wirelessinterface schedule.
 21. A circuit comprises: a plurality of wirelessinterface circuits that communicate packetized data to a correspondingplurality of external devices in accordance with a correspondingplurality of wireless communication protocols, wherein the plurality ofwireless interface circuits includes at least one module that is shared,the at least one module having a first state where the at least onemodule is operational and a second state corresponding to a low-powerstate; and wherein the plurality of wireless interface circuits operatein accordance with a wireless interface schedule that includes a firsttime interval wherein the plurality of wireless interface circuitscontemporaneously use the at least one module in the first state and asecond time interval wherein the at least one module is in the secondstate.
 22. The circuit of claim 21 wherein the plurality of wirelesscommunication protocols includes an 802.11 protocol used by a firstwireless interface circuit of the plurality of wireless interfacecircuits, and wherein the first wireless interface circuit scans for anincoming beacon during the first time interval.
 23. The circuit of claim21 wherein the plurality of wireless communication protocol includes awireless pico-network protocol used by a second wireless interfacecircuit of the plurality of wireless interface circuits, and wherein thesecond wireless interface circuit performs a page scan during the firsttime interval.
 24. The circuit of claim 21 wherein the at least onemodule includes at least one of, an oscillator, and a low noiseamplifier.
 25. The circuit of claim 21 further comprising: a pluralityof signal lines, coupled to the plurality of wireless interfacecircuits, that communicate cooperation data between the plurality ofwireless interface circuits, wherein the cooperation data relates tocooperate use of the at least one module.
 26. The circuit of claim 21further comprising: a processing module, coupled to the plurality ofwireless interface circuits, that generates the wireless interfaceschedule.
 27. The circuit of claim 21 wherein the at least one module ispowered off during the second time interval.